Definition of Neutral Conductor

[bennie]

Go to; http://dictionary.reference.com/search?q=Neutral


My definition of a neutral conductor is;

Any current carrying conductor that has a net voltage to ground of zero measured at the service ground bus.

 

[hbiss]

Re: Definition of Neutral Conductor

How about the grounded current carrying conductor?

 

[earlydean]

Re: Definition of Neutral Conductor

How about: A system or circuit conductor that is intentionally grounded and is a common return path, after the load, for all ungrounded conductors.

 

[Ed MacLaren]

Re: Definition of Neutral Conductor

Seems to me that is just another way of saying "the grounded conductor", however, that definition would include the grounded conductor of a 2-wire circuit, and the grounded conductor of a three phase circuit supplied from a corner-grounded delta secondary.

It is difficult to come up with a short, concise definition that is technically correct. I would suggest this one-

"A conductor (when one exists) of a polyphase circuit, or a single phase 3-wire circuit, which is intended to have a voltage such that the voltage differences between it and two or more ungrounded conductors are approximately equal in magnitude and equally spaced in phase."

Ed

 

[gwz2]

Re: Definition of Neutral Conductor

Ed,

Good defintion.

I do question the situation of 3? 4W Delta ( high leg ) with that definition.

gwz2

 

[bennie]

Re: Definition of Neutral Conductor

I base my definition on No 6, of the reference documents. The phases are not at war, sex is not involved, chemical content is irelevant, the color is not important, some neutral conductors are bare.

No. 6 is all that is left.

 

[bennie]

Re: Definition of Neutral Conductor

Please note No.3. A neutral conductor has to belong to the active phase or phases. The definition in No.3 states that "neutral" is; "Belonging to neither kind"; not one thing or the other.

This definition can not apply to an electrical circuit, and is incorrect to use in that manner.

[ October 21, 2003, 06:38 PM: Message edited by: bennie ]

 

[crash]

Re: Definition of Neutral Conductor

These are interesting statements Bennie. You stated "belonging to neither kind".
My understanding of a 240V 3phase 4wire delta, is that all 120V loads would be connected between Line B (or Line C) and the grounded conductor. 3 phase loads would be connected betwween Line A, Line B and Line C. A load would not normally be connected between Line A and the grounded conductor ( it is my understanding that panels in these systems are designed to make this difficult ). Hence the grounded conductor "belongs" to Line B and Line C, and does not belong to Line A. Therefore it must not be a true "neutral".

 

[Ed MacLaren]

Re: Definition of Neutral Conductor

I do question the situation of 3? 4W Delta ( high leg ) with that definition.

This is the way that we are required to arrange the branch circuits in a facility that is supplied from a 4-wire delta transformer, where I live. (Sketch)
Can anyone honestly say that the feeder to the single phase panel does not incorporate a neutral conductor?

Ed

 

[bennie]

Re: Definition of Neutral Conductor

Crash: If the definition No.3 stated; " Belonging equally to two or more active conductors instead of belonging to neither side, I would form a different perspective.

I say that a conductor that belongs to neither side is an open circuit and the whole issue is ludicrous.

A neutral conductor can be ungrounded and not have a potential to ground. Only definition No.6 is relevant to this subject.

[ October 21, 2003, 09:35 PM: Message edited by: bennie ]

 

[charlie]

Re: Definition of Neutral Conductor

What do you think about, "Neutral Conductor. A conductor, other than a grounding conductor, that is connected to the common point of a wye connection in a polyphase system or the point of a symmetrical system which is normally at zero voltage." This is proposal 1-122 as accepted by CMP-1 and is open for your comments.

Bennie, I expect to see your comment published in the ROC (Report on Comments).

 

[bennie]

Re: Definition of Neutral Conductor

Charlie: A neutral conductor is a load carrying conductor with a net charge of zero to ground.

To me, this covers everything.

A static detector will not activate on a neutral, if it is grounded or ungrounded.

I'm sorry, I am not qualified to oppose the committees. That is what I am told.

 

[pierre]

Re: Definition of Neutral Conductor

If the definition of a neutral conductor is going to be adopted, it should be able to be understood by the 'average' person who uses the NEC. It should be concise, but not vague so as to be twisted by users who find the 'loopholes' to a meaning that is not definitive.

Pierre

 

[crash]

Re: Definition of Neutral Conductor

Ed you are correct , in the single phase panel board the grey conductor is a true neutrol conductor, however the red conductor is not present in this panel board. in the three phase panel board the grey conductor would not be considered to be a true neutrol conductor, however the grey conductor is not present in this panel board.

 

[gwz2]

Re: Definition of Neutral Conductor

Just questioning.

Is the transformer configuration, 3? 4W Delta, not the System Source and the High Leg must be considered even if not part of the individual panelboards ?

I certain agree that the 3W panelboard with the Neutral is treated as a 1? panelboard, but does it meet the system definition ?

I would, like others, like to see an acceptable, precise NEUTRAL definition.

gwz2

 

[roger]

Re: Definition of Neutral Conductor

Glenn, In a "Three Wire" circuit of a "Center Grounded Winding" of a "Delta" configuration of windings, the grounded conductor performs the same as it would in any single grounded winding.

Why would the high leg be a consideration here?

Yes, it would have an unstable potential difference to the "Grounded Conductor" but so would any ungrounded winding from across town that wouldn't have anything to do with the winding serving the single phase panel.

My point is, the other two windings are not part of the single phase grounded (neutral) conductor's reference.

I think (I usually get in trouble when this starts ) the terminology "4 wire Delta is the real problem. Let's throw this term away and use something like "Delta Single Phase Source"

EX: The lighting is fed from a "Delta Single Phase Source"

Roger

[ October 22, 2003, 09:41 AM: Message edited by: roger ]

 

[earlydean]

Re: Definition of Neutral Conductor

What can we call the gray wire in the configuration, if not the neutral? The grounded conductor? It doesn't seem right.

It is "neutral" to phases A and C, and even when we have a panel with all three "hots" and the gray wire, it is called the neutral, knowing it is not really neutral to all phases equally.

 

[charlie]

Re: Definition of Neutral Conductor

Earl, what happened to taking the grounded conductor (the one you are calling the neutral) to both services so 250.24(B) can be complied with?

 

[bennie]

Re: Definition of Neutral Conductor

There is no dictionary that indicates the word neutral means being equal to both sides. The meaning is actually; not associated with either side. This definition is not applicable in physical science.

This definition is a world political issue. Case in point; Switzerland has declared neutrality in all wars. This means the country does not have any association with any of the warring factions. It does not mean the country helps both sides equally.

In physical science; Neutral is when there is no difference in electrostatic charge between two objects.

 

[charlie b]

Re: Definition of Neutral Conductor

Originally posted by bennie: In physical science; Neutral is when there is no difference in electrostatic charge between two objects.

True, but our profession is not that of the physical scientist. Physical science, or more specifically electrical science, forms the basis of what we do, and sets limits that we cannot circumvent. But the link in your original post does not give all of the available definitions of the word ?neutral.? My copy of the ?McGraw-Hill Dictionary of Scientific and Technical Terms? (fifth edition, 1994) defines 54 separate phrases that include that word ?neutral? in some form.

To be precise, and I think precision is needed here, the word ?neutral? should not be used (in our intended context) as a noun. It is a common, if sloppy, conversational habit, but it is not proper. The word ?neutral? is an adjective, intended to modify a noun such as ?conductor.? What we are really talking about here is a ?neutral conductor.? The dictionary I mention above defines that term as follows: ?A conductor of a polyphase circuit or of a single-phase, three-wire circuit which is intended to have a potential such that the potential differences between it and each of the other conductors are approximately equal in magnitude and are also equally spaced in phase.?